In which of the following compounds, an element exhibits two different oxidation states.
Hà
NH4OH
NH, NO
PH

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.

Summarize possible ways in which phases of matter could combine to form a solution.

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?